Get the Latest Kubernetes Cheat Sheet for Simplifying Container Orchestration

Get the Latest Kubernetes Cheat Sheet for Simplifying Container Orchestration

Kubernetes is an open-source container-orchestration system for automating application deployment, scaling, and management. It was originally designed by Google and is now maintained by the Cloud Native Computing Foundation.

Common Commands

NameCommand
Run curl test temporarilykubectl run --rm mytest --image=yauritux/busybox-curl -it
Run wget test temporarilykubectl run --rm mytest --image=busybox -it
Run nginx deployment with 2 replicaskubectl run my-nginx --image=nginx --replicas=2 --port=80
Run nginx pod and expose itkubectl run my-nginx --restart=Never --image=nginx --port=80 --expose
Run nginx deployment and expose itkubectl run my-nginx --image=nginx --port=80 --expose
Set namespace preferencekubectl config set-context <context_name> --namespace=<ns_name>
List pods with nodes infokubectl get pod -o wide
List everythingkubectl get all --all-namespaces
Get all serviceskubectl get service --all-namespaces
Show nodes with labelskubectl get nodes --show-labels
Validate yaml file with dry runkubectl create --dry-run --validate -f pod-dummy.yaml
Start a temporary pod for testingkubectl run --rm -i -t --image=alpine test-$RANDOM -- sh
kubectl run shell commandkubectl exec -it mytest -- ls -l /etc/hosts
Get system conf via configmapkubectl -n kube-system get cm kubeadm-config -o yaml
Get deployment yamlkubectl -n denny-websites get deployment mysql -o yaml
Explain resourcekubectl explain pods, kubectl explain svc
Watch podskubectl get pods -n wordpress --watch
Query healthcheck endpointcurl -L https://127.0.0.1:10250/healthz
Open a bash terminal in a podkubectl exec -it storage sh
Check pod environment variableskubectl exec redis-master-ft9ex env
Enable kubectl shell autocompletionecho "source <(kubectl completion bash)" >>~/.bashrc, and reload
Use minikube dockerd in your laptopeval $(minikube docker-env), No need to push docker hub any more
Kubectl apply a folder of yaml fileskubectl apply -R -f .
Get services sorted by namekubectl get services –sort-by=.metadata.name
Get pods sorted by restart countkubectl get pods –sort-by=’.status.containerStatuses[0].restartCount’
Ubuntu install kubectl"deb https://apt.kubernetes.io/ kubernetes-xenial main"

Check Performance

NameCommand
Get node resource usagekubectl top node
Get pod resource usagekubectl top pod
Get resource usage for a given podkubectl top <podname> --containers
List resource utilization for all containerskubectl top pod --all-namespaces --containers=true

Resources Deletion

NameCommand
Delete podkubectl delete pod/<pod-name> -n <my-namespace>
Delete pod by forcekubectl delete pod/<pod-name> --grace-period=0 --force
Delete pods by labelskubectl delete pod -l env=test
Delete deployments by labelskubectl delete deployment -l app=wordpress
Delete all resources filtered by labelskubectl delete pods,services -l name=myLabel
Delete resources under a namespacekubectl -n my-ns delete po,svc --all
Delete persist volumes by labelskubectl delete pvc -l app=wordpress
Delete statefulset only (not pods)kubectl delete sts/<stateful_set_name> --cascade=false

Log & Conf Files

NameComment
Config folder/etc/kubernetes/
Certificate files/etc/kubernetes/pki/
Credentials to API server/etc/kubernetes/kubelet.conf
Superuser credentials/etc/kubernetes/admin.conf
kubectl config file~/.kube/config
Kubernets working dir/var/lib/kubelet/
Docker working dir/var/lib/docker/, /var/log/containers/
Etcd working dir/var/lib/etcd/
Network cni/etc/cni/net.d/
Log files/var/log/pods/
log in worker node/var/log/kubelet.log, /var/log/kube-proxy.log
log in master nodekube-apiserver.log, kube-scheduler.log, kube-controller-manager.log
Env/etc/systemd/system/kubelet.service.d/10-kubeadm.conf
Envexport KUBECONFIG=/etc/kubernetes/admin.conf

Pod

NameCommand
List all podskubectl get pods
List pods for all namespacekubectl get pods -all-namespaces
List all critical podskubectl get -n kube-system pods -a
List pods with more infokubectl get pod -o wide, kubectl get pod/<pod-name> -o yaml
Get pod infokubectl describe pod/srv-mysql-server
List all pods with labelskubectl get pods --show-labels
List running podskubectl get pods –field-selector=status.phase=Running
Get Pod initContainer statuskubectl get pod --template '{.status.initContainerStatuses}' <pod-name>
kubectl run commandkubectl exec -it -n “$ns” “$podname” – sh -c “echo $msg >>/dev/err.log”
Watch podskubectl get pods -n wordpress --watch
Get pod by selectorkubectl get pods –selector=”app=syslog” -o jsonpath='{.items[*].metadata.name}’
List pods and imageskubectl get pods -o=’custom-columns=PODS:.metadata.name,Images:.spec.containers[*].image’
List pods and containers-o=’custom-columns=PODS:.metadata.name,CONTAINERS:.spec.containers[*].name’

Label & Annontation

NameCommand
Filter pods by labelkubectl get pods -l owner=denny
Manually add label to a podkubectl label pods dummy-input owner=denny
Remove labelkubectl label pods dummy-input owner-
Manually add annonation to a podkubectl annotate pods dummy-input my-url=https://dennyzhang.com

Deployment & Scale

NameCommand
Scale outkubectl scale --replicas=3 deployment/nginx-app
online rolling upgradekubectl rollout app-v1 app-v2 --image=img:v2
Roll backupkubectl rollout app-v1 app-v2 --rollback
List rolloutkubectl get rs
Check update statuskubectl rollout status deployment/nginx-app
Check update historykubectl rollout history deployment/nginx-app
Pause/Resumekubectl rollout pause deployment/nginx-deployment, resume
Rollback to previous versionkubectl rollout undo deployment/nginx-deployment

Quota & Limits & Resource

NameCommand
List Resource Quotakubectl get resourcequota
List Limit Rangekubectl get limitrange
Customize resource definitionkubectl set resources deployment nginx -c=nginx --limits=cpu=200m
Customize resource definitionkubectl set resources deployment nginx -c=nginx --limits=memory=512Mi

Service

NameCommand
List all serviceskubectl get services
List service endpointskubectl get endpoints
Get service detailkubectl get service nginx-service -o yaml
Get service cluster ipkubectl get service nginx-service -o go-template='{.spec.clusterIP}’
Get service cluster portkubectl get service nginx-service -o go-template='{(index .spec.ports 0).port}’
Expose deployment as lb servicekubectl expose deployment/my-app --type=LoadBalancer --name=my-service
Expose service as lb servicekubectl expose service/wordpress-1-svc --type=LoadBalancer --name=ns1

Secrets

NameCommand
List secretskubectl get secrets --all-namespaces
Generate secretecho -n 'mypasswd', then redirect to base64 -decode
Create secret from cfg filekubectl create secret generic db-user-pass –from-file=./username.txt

StatefulSet

NameCommand
List statefulsetkubectl get sts
Delete statefulset only (not pods)kubectl delete sts/<stateful_set_name> --cascade=false
Scale statefulsetkubectl scale sts/<stateful_set_name> --replicas=5

Volumes & Volume Claims

NameCommand
List storage classkubectl get storageclass
Check the mounted volumeskubectl exec storage ls /data
Check persist volumekubectl describe pv/pv0001
Copy local file to podkubectl cp /tmp/my <some-namespace>/<some-pod>:/tmp/server
Copy pod file to localkubectl cp <some-namespace>/<some-pod>:/tmp/server /tmp/my

Events & Metrics

NameCommand
View all eventskubectl get events --all-namespaces
List Events sorted by timestampkubectl get events –sort-by=.metadata.creationTimestamp

Node Maintenance

NameCommand
Mark node as unschedulablekubectl cordon $NDOE_NAME
Mark node as schedulablekubectl uncordon $NDOE_NAME
Drain node in preparation for maintenancekubectl drain $NODE_NAME

Namespace & Security

NameCommand
List authenticated contextskubectl config get-contexts, ~/.kube/config
Set namespace preferencekubectl config set-context <context_name> --namespace=<ns_name>
Load context from config filekubectl get cs --kubeconfig kube_config.yml
Switch contextkubectl config use-context <cluster-name>
Delete the specified contextkubectl config delete-context <cluster-name>
List all namespaces definedkubectl get namespaces
List certificateskubectl get csr

Network

NameCommand
Temporarily add a port-forwardingkubectl port-forward redis-izl09 6379
Add port-forwaring for deploymentkubectl port-forward deployment/redis-master 6379:6379
Add port-forwaring for replicasetkubectl port-forward rs/redis-master 6379:6379
Add port-forwaring for servicekubectl port-forward svc/redis-master 6379:6379
Get network policykubectl get NetworkPolicy

Patch

NameSummary
Patch service to loadbalancerkubectl patch svc $svc_name -p '{"spec": {"type": "LoadBalancer"}}'

Extenstions

NameSummary
List api groupkubectl api-versions
List all CRDkubectl get crd
List storageclasskubectl get storageclass
List all supported resourceskubectl api-resources

Components & Services

1. Services on Master Nodes

NameSummary
kube-apiserverexposes the Kubernetes API from master nodes
etcdreliable data store for all k8s cluster data
kube-schedulerschedule pods to run on selected nodes
kube-controller-managernode controller, replication controller, endpoints controller, and service account & token controllers

2. Services on Worker Nodes

NameSummary
kubeletmakes sure that containers are running in a pod
kube-proxyperform connection forwarding
Container RuntimeKubernetes supported runtimes: Docker, rkt, runc and any OCI runtime-spec implementation.

3. Addons: pods and services that implement cluster features

NameSummary
DNSserves DNS records for Kubernetes services
Web UIa general purpose, web-based UI for Kubernetes clusters
Container Resource Monitoringcollect, store and serve container metrics
Cluster-level Loggingsave container logs to a central log store with search/browsing interface

4. Tools

NameSummary
kubectlthe command line util to talk to k8s cluster
kubeadmthe command to bootstrap the cluster
kubefedthe command line to control a Kubernetes Cluster Federation
Kubernetes ComponentsLink: Kubernetes Components

Thanks for reading to the end; I hope you gained some knowledge. ❤️🙌

- Rushikesh Mashidkar💕

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